In spite of the many publications which have appeared of late years on the heredity in the pea, but a few of the hereditary differences have been analysed, while the research on the localization of the factors is still in its initial stage. So the pea of which so many forms occur, for the time being presents plenty of material to start a research. I have set myself the task of making the completest possible analysis of the flower colour differences and of the differences in length of stem. As regards the flower colour I build on the researches of H. TEDIN, who was kind enough to spare me his forms for my research. In a way it is a happy coincidence that the number of flower colours of the pea is rather small, which renders the research surveyable. Of the known forms I now possess a fairly complete collection, pains being constantly taken to supplement the collection. The research on the heredity of the length of stem is still in its initial stage. So vast a number of forms exist that I have more material at my disposal than can be worked up. The researches were made in the Genetic Institute of the State University of Groningen.